@Lord Imperialis: That's largely true but the FLMM script also edits several files directly and this is a reasonably important step. This isn't just for the player options.
For you folk who are running Vista and are having trouble installing the mod with FLMM 1.3, can you try FLMM 1.5 beta. I'm aware this version has a few quirks but it will install the mod correctly. You can get it here: http://fllistserver.com/news/category/flmm/
If you have installation trouble, then post a screen shot of FLMM when it fails and as much detail about your computer installation as possible. This makes it much easier to diagnose the problem.
(It's possible to get the author from FLMM to fix it if he knows what is broken.)
Proud member of "the most paranoid group of people in the community"
Ah, sorry for that, my mistake.
Luckily it's working alright here, after I turned off User Account Control (Silly thing stops you from unpacking rars etc properly sometimes, claiming you don't have the permission..when you do)
I see. You turned off UAC...you will need to do that if you're not running FLMM with the "Run As Administrator" option ticked.
For Vista guys: always run FLMM by right clicking on the shortcut and selecting the "Run As Administrator" tick-box. This will almost certainly be the cause of your problems.
I think FLMM 1.5 includes a "Run As Administrator" thingy in its manifest so you don't need to do this. If someone tries 1.5 and it works for them where 1.3/1.4 didn't then post here.
Proud member of "the most paranoid group of people in the community"